It measured 2.17m (7ft 1ins) and was found floating in waist-deep water by the beach as the friends enjoyed a holiday in Kingsand, Cornwall.

The species is critically endangered and it is illegal to catch or sell them in British waters – so the friends won't see any money for their epic find.

Last year a 4ft 6in long barrel-shaped fish was found floundering off Torquay – around half the size of the one the girls found – was valued at £500,000.

Sadly for the girls – who all met at Oxford Brookes University – the fish was taken by officials from Marine Management Organisation, part of the Department for Environment, Food and Rural Affairs.

HEAVE HO: The fish measured over 7ft in length [SWNSS]

“I shouted 'shark' but then we saw whatever it was was dead and we had a closer look and hauled it up across the kayaks”

Sarah Little

Sarah, from Tunbridge Wells, said: "We took the kayaks out at 12pm and we'd only just got in the water and were messing around being silly when we saw this massive thing floating on the sea bed.

"I shouted 'shark' but then we saw whatever it was was dead and we had a closer look and hauled it up across the kayaks. It was massive.

"We dragged it to shore and by this time a large crowd had gathered on the beach and saw what we had.

"We tried to flip it over but it was too heavy so four men had a go – and they couldn't lift it either. There was lots of faffing about."

Somebody in the neighbouring village of Cawsand had reported seeing what they thought was a dolphin trying to beach itself the night before, which now seems possibly to have been the fish.

Claire Wallerstein, a local strandings officer who works for the Cornwall Wildlife Trust, said: "The girls were wondering if they could sell it but we explained they probably couldn't because of certain laws and a local fisherman took it off to cut up and use for bait in his crab pots.

"But then we heard back and were told it was a bluefin so the fisherman has kept it in his fridge for now.

"It'll be taken to the University of Exeter's site in Falmouth where it will be studied and undergo toxicology tests."

CATCH OF THE DAY: Unfortunately the girls will not see any profit from their fishy find [SWNS]

The find has been reported to the authorities and the fish will be transported to the University of Exeter tomorrow to be studied by scientists.

Bluefin tuna are rarely seen in the English Channel and over the past few decides numbers have declined by up to 82% largely due to over fishing.

The specimen is still a tiddler compared to some bluefin tuna which have been known to grow over eight feet long and weigh more than 950lb.

A spokesman for the Marine Conservation Society, confirmed that bluefin tuna are rare visitors this far north and that there was an EU ban on selling them.

He said: "This is a rare event, as Atlantic bluefin are only sporadically seen and reported in the English Channel.

"They are rare because they have been fished heavily in recent decades, and the species is close to extinction."